In response to the recent public health scare involving the identification of type-2 polio virus contamination in circulating vaccines, the Union Health Ministry is probing the incident.
The source of the vaccine was traced back to an Indonesian pharmaceutical company PT Bio Farma. These vaccines were then purchased by Indian company Biomed Pvt. Ltd. who put the vaccine into circulation.
The Union Health Ministry has opted to send an inspection team directly to the Indonesian company to assess how the type-2 strain entered circulation. Such a move is necessary to avoid further incidents, as well as to ascertain as to whether more batches may have been contaminated in a similar manner.
A Central Drugs Standards Control Organisation (CDSCO) team has already carried out a detailed investigation at the factory of Biomed Pvt. Ltd. in Ghaziabad. The director of Biomed Pvt. Ltd. was arrested following the incident, though later freed on bail. The government is considering filing a special leave petition in the Supreme Court against the Ghaziabad district court’s decision to allow for the bailing of the director.
The Union Health Ministry confirmed the contamination of a number of batches of vaccines with type-2 poliovirus vaccine had occurred in three states: Maharashtra, Telangana and Uttar Pradesh. The last case of type-2 wild poliovirus was detected in 1999. The last polio case due to wild poliovirus in the country was detected on January 13, 2011.
This is of particular concern due to the fact that type-2 vaccine is no longer in use. In September 2015, the World Health Organization (WHO) declared type-2 polio fully eradicated. On the WHO’s advice, India phased out the type-2 virus from its oral vaccines in April 2016.
“The vaccine virus is a problem because of all the oral vaccine strains, the strain of type-2 is most likely to cause vaccine-associated paralytic polio, which is why it was removed in the first place,” said public health researcher Sylvia Karpagam. Due to the vaccine for type-2 polio no longer being in circulation, immunity levels to this strain will have fallen. This presents a greater risk of the vaccine-derived strain found in sewage samples across the Indian states causing a widespread outbreak.
India is a prime example of what can be achieved through grassroot vaccination campaigns. For vaccines to have circulated across a population in excess of a billion, allowing for the eradication of polio, is a testament to both national and global political will to see the vaccination campaign through to the end goal of eradication.
The contamination has occurred in the run up to World Polio Day. The incident stresses the importance of vigilance against diseases, even following their eradication, as a lapse in standards such as this could have potentially led to a resurgence in the disease.